Sulfate-attack in Concrete

Dissolved soluble sulfates in waters – e.g. in rivers, sewer units and lines – react with certain components of Portland cement to form an over-sized reaction product. The reaction product incubates in typically voids, grows, and burst out of the voids, creating delamination in the concrete. Several such accumulated processes causes a weakening of the concrete.


Several growth of deleterious reaction products in concrete


Crystal growths of ettringite in voids of concrete as shown by scanning electron microscopy (SEM)


An accretion of crystalline hydration products bursting out from a void to initiate and propagate cracks.


A 6-year old concrete placed for an airport runway was removed and replaced due to sulfate attack.